Solutions to the four major fault problems of the extruder

The extruder is an important equipment for plastic molding, processing and granulation. The normal use of the extruder can give full play to the efficiency of the machine and maintain a good working condition. Careful maintenance is required to prolong the service life of the machine.

The main faults of the extruder are abnormal noise and abnormal vibration caused by abnormal wear, wear or damage of transmission parts, poor lubrication, etc., as well as foreign matter stuck, link blockage, etc.

In order to avoid failures, in addition to daily maintenance, maintenance and overhaul in strict accordance with the requirements, you also need to know these:

1. Wear of the extruder screw

Cause of wear

The normal wear of the screw and barrel of the screw extruder mainly occurs in the feeding area and the metering area. The main cause of wear is caused by dry friction between the sliced particles and the metal surface. When the slices are heated and softened, the wear is reduced.

The abnormal wear of the screw and the barrel will occur when the screw rings and foreign objects are stuck, and the ring means that the screw is locked by the condensed material. If the screw extruder lacks a good protection device, the strong driving force may break the screw, and the stuck will produce an unusually large resistance, causing serious damage to the screw surface and serious scratches to the barrel, and the scratches of the barrel are difficult to repair. The barrel is designed to ensure a longer service life than the screw. For the normal wear of the barrel, it is generally not repaired. The method of repairing the screw thread is often used to restore the radial clearance between the inner hole of the barrel and the outer diameter of the screw.

The solution to screw wear

The local damage of the screw thread is repaired by the method of surfacing special anti-wear and anti-corrosion alloy. Generally, inert gas shielded welding and plasma argon arc welding are used, and metal spraying technology can also be used for repair. First grind the outer surface of the worn screw to a depth of about 1.5mm, and then surfacing the alloy layer to a sufficient size to ensure sufficient machining allowance. Finally, grind the outer circumference of the screw and the flank of the thread to the original size of the screw.

2. Abnormal noise

(1) If it occurs in the reducer, it may be caused by bearing damage or poor lubrication, or it may be caused by gear wear, improper installation and adjustment, or poor meshing.

It can be solved by replacing bearings, improving lubrication, replacing gears or adjusting gear meshing conditions.

(2) If the noise is a sharp scratching sound, the position of the barrel should be considered skewed, causing the possibility of scraping the shaft head and the drive bushing.

It can be solved by adjusting the barrel.

(3) If the barrel makes noise, it may be that the screw is bent and swept or the set temperature is too low, causing excessive friction of solid particles.

It can be dealt with by straightening the screw or increasing the set temperature.

3. Abnormal vibration

If this situation occurs at the reducer, it is caused by the wear of the bearing and the gear, which can be solved by replacing the bearing or gear;

If it occurs at the barrel, it is because the material is mixed with hard foreign matter. It is necessary to check the cleanliness of the material. If necessary, a strong magnetic device is installed in the hopper to absorb iron filings.

4. Ring blockage at screw inlet

This kind of failure is mainly caused by the interruption of cooling water or insufficient flow. It is necessary to check the cooling system and adjust the cooling water flow and pressure to the specified requirements.

It is also possible that the large recycled material blocks in the raw material block the feeding port, and the feeding port needs to be cleaned.

Nanjing Haisi Extrusion Equipment Co., Ltd. is a professional manufacturer of plastic extruder. We supply turn-key project solutions and professional after sales service. Any interest please feel free to contact us!